1. Field of the Invention
The present invention relates to a library apparatus having a housing into which a tray, having plural storage slots storing respective, plural cartridge media, is movable to a closed position at which an accessor selectively moves an individual cartridge medium between the tray and a drive mechanism in accordance with a move command issued from a host computer. More particularly, the invention relates to such a library apparatus having a mail slot mode in which the tray is opened selectively to a mail slot access position for manual insertion of a single cartridge medium into the mail slot or manual removal thereof from the mail slot, in respective insertion and removal operations in which the medium is conveyed between the mail slot and a respective storage slot, controlled by corresponding move commands from the host computer and whereby the potential of human error in cartridge media exchange operations is eliminated.
2. Description of the Related Art
In recent years, due to the increased use of graphics and large software programs and the large amounts of data required therefor, optical disks have become a popular storage medium for computers, in view of their large memory capacities, exceeding 200 MB; further, they may be provided as removable cartridges that can be used with different optical disk drives. Their popularity has further increased with the recent development of 3.5-inch optical disk drives having cost and access speeds comparable to those of hard disk drives of just a few years ago. (Hereinafter, the terms "optical disk", "OM cartridges", "cartridge medium" or "media", etc., are used interchangeably.)
A single optical disk cartridge nevertheless has a finite memory capacity which may be inadequate for graphics and other large software programs; thus, desk-top type optical disk library apparatuses have become available which accommodate therein a plurality of optical disk cartridges which are individually selected by a robot hand and loaded thereby into an optical disk drive. An example thereof is a 3.5-inch magneto-optic (MO) disk library apparatus M2532B made by Fujitsu Ltd. In this desk-top type optical disk library apparatus, three racks can be mounted in a tray of the apparatus; an individual such rack has twelve (12) slots which can receive twelve (12) corresponding MO cartridges. Consequently, a total of thirty-six (36) MO cartridges can be received in the tray.
Usually, the MO cartridges are inserted into, or ejected from, the library apparatus on a rack-by-rack basis. Then, when an ejection switch, provided on a control panel of the apparatus, is depressed, the tray is pulled out from its fully inserted, or loaded, position within the housing of the apparatus so as to extend from the front face of the apparatus in a fully opened state, or position. Each rack is detached from the tray, in the fully opened state of the tray, MO cartridges are ejected from and/or are inserted into the respective slots of the rack, and the rack then is returned to the tray. When the ejection switch is depressed, again, the tray is retracted, or advanced into its fully loaded position within the housing thereby completing the preparation for reading or writing operations relative to the newly provided, i.e., exchanged, MO cartridge media.
In one illustrative activity using such a library apparatus, there is a requirement for exchanging the cartridge media stored in the library apparatus, one by one, and processing the data. For example, when data of a number of branches of a company distributed all over Japan is processed in a main office of the company by using respective MO cartridges from those branches, on a monthly basis, the MO cartridge of a given branch for a current month is exchanged for a medium cartridge of the same branch for the previous month which is currently stored in the library apparatus.
As for the activity of exchanging each such MO cartridge, the tray is fully opened by operating the ejection switch and, since a respective, fixed slot number has been established for every branch, the operator checks the respective slot number for the branch name of the MO cartridge to be exchanged, finds the respective slot by counting the slots in the racks in the tray (or observing a location number for the slot), and then exchanges the new for the prior, MO cartridge.
The work of exchanging the MO cartridge, which is executed by finding the slot position of the cartridge to be exchanged by counting the slot numbers of the racks in the tray, presents problems such as imposing a large work burden on the operator and causing mistakes in the work such that an exchange of an MO cartridge at a wrong slot is apt to occur. Usually, not merely a single library apparatus but, rather, several library apparatuses are connected to the host computer. The number of MO cartridges to be exchanged accordingly increases and, consequently, further increases the work burden and the frequency of the occurrences of mistakes in making such exchanges. The present invention arose in consideration of solving the above problems of the prior art.